Personal Research Database

Full Text: 2007\J Haz Mat141, 202.pdf

Abstract: Mining of mineral ore and disposal of resulting waste tailings pose a significant risk to the surrounding environment. The objective of this work is to demonstrate the feasibility to remove heavy metals from mine tailings with the use of bioleaching and meanwhile to investigate the effect of solids concentration on removal of heavy metals from mine tailings by indigenous sulfur-oxidizing bacteria and the transformation of heavy metal forms after the bioleaching process. This work showed the laboratory results of bioleaching experiments on Pb-Zn-Cu mine tailings. The results showed that 98.08% Zn, 96.44% Cu, and 43.52% Pb could be removed from mine tailings by the bioleaching experiment after 13 days at 1% (w/v) solids concentration and the rates of pH reduction, ORP rise and sulfate production were reduced with the increase of solids concentration, due to the buffering capacity of mine tailing solids. The results also indicated that solid concentration 1% was found to be best to bacterial activity and metal solubilization of the five solids concentration tested (1%, 2%, 5%, 8% and 10%) under the chosen experimental conditions. In addition, the bioleaching had a significant impact on changes in partitioning of heavy metals. (c) 2006 Elsevier B.V All rights reserved.

Keywords: Activity, Bacteria, Bioleaching, Capacity, Concentration, Contaminated Sediment, Disposal, Environment, Experiment, Heavy Metal, Heavy Metals, Impact, Metal, Metals, Mine, Mine Tailings, Mineral, Partitioning, Pb, pH, Production, Reduction, Removal, Risk, Sewage-Sludge, Soils, Solids Concentration, Solubilization, Sulfate, Sulfur-Oxidizing Bacteria, Surrounding Environment, Waste

? Niu, C.M., Wu, W.H., Wang, Z., Li, S.M. and Wang, J.Q. (2007), Adsorption of heavy metal ions from aqueous solution by crosslinked carboxymethyl konjac glucomannan. Journal of Hazardous Materials, 141 (1), 209-214.

Full Text: 2007\J Haz Mat141, 209.pdf

Abstract: Crosslinked carboxymethyl konjac glucomannan (CMKGM) with degrees of substitution (DS) 0.265 and 0.550 were prepared through reaction of monochloroacetic acid (MCA), konjac glucomannan (KGM) and epichlorohydrin and used to adsorb CU²⁺ Pb²⁺ and Cd²⁺ ions from the aqueous solutions. Regardless of the metal ion species, the adsorption capacity rapidly reached equilibrium within 20 min and adsorption followed secondorder kinetic equation. The effect of pH on adsorption was apparent, the appropriate range was 5-6. The adsorptions of three metal ions are well followed as the Langmuir adsorption isotherm. The maximum adsorption capacity (Q(m)) and Langmuir constant (b) of CMKGM (DS = 0.550) for Pb²⁺ were 41.7 mg/g and 0.305 mg/L. These values were higher than those for Cu²⁺ and Cd²⁺. Among the tested ions, the order of adsorption capacity was Pb²⁺ > Cu²⁺ > Cd²⁺ in mass basis. The regeneration study indicates that CMKGM could be used repeatedly without significantly changing their adsorption capacities and desorption percentage. (c) 2006 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Capacity, Adsorption Isotherm, Capacity, Chitosan Beads, Crosslinked Carboxymethyl Konjac Glucomannan, Cu²⁺, Derivatives, Desorption, Equilibrium, Heavy Metal, Heavy Metal Ion, Heavy Metal Ions, Ion, Ion Species, Isotherm, Isothermal Adsorption, Kinetic, Kinetics, Langmuir, Langmuir Adsorption Isotherm, Metal, Metal Ions, pH, Range, Reaction, Reactive Dye, Regeneration, Removal, Starch, Waste, Water

? Khan, M.N. and Wahab, M.F. (2007), Characterization of chemically modified corncobs and its application in the removal of metal ions from aqueous solution. Journal of Hazardous Materials, 141 (1), 237-244.

Full Text: 2007\J Haz Mat141, 237.pdf

Abstract: The objective of this work was to convert corncobs to activated carbon by low temperature chemical treatment for removing copper from wastewater. The parameters for developing a new adsorbent i.e. sorption capacity, selectivity, regenerability, suspension test, and kinetics were investigated. All studies were performed in batch experiments. Removal of copper from aqueous solutions varied with the amount of adsorbent, metal ion concentration, agitation time, solution pH and the species of copper present. It was found that the effect of temperature was very small. The Langmuir model was found to best fit the equilibrium isotherm data. Kinetics of copper removal at two different temperatures obeyed Lagergren pseudo-first-order equation. Effect of water hardness, other cations (Pb²⁺ and Zn²⁺) on copper removal was also studied. Experiments with anionic and cationic complexes of copper showed that anionic copper species are not removed at all by the prepared material. To observe the nature of surface and pore structure scanning electron microscope (SEM) images of modified corncobs were used. To study the interaction forces between the adsorbent and the metal ion functional group analysis with infrared spectroscopy and proximate analysis were carried out. In addition, recovery of the metals ion and regeneration of spent adsorbent was possible by acidified hydrogen peroxide. Since the uptake capacity of the prepared adsorbent is 26 mg Cu/g for copper, it can be a potential adsorbent for removing and recovering other heavy metal ions from contaminated wastewaters. The sorption capacity of the treated corncobs for copper was better than the reported capacity of other activated carbons prepared from agricultural sources. (c) 2006 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Activated Carbons, Adsorbent, Adsorption, Agitation, Agricultural, Analysis, Application, Aqueous Solution, Aqueous Solutions, Batch, Batch Experiments, Capacity, Carbon, Characterization, Chemical, Chemical Modification, Chemical Treatment, Concentration, Copper, Copper Removal, Corncob, Cu(II), Data, Developing, Equilibrium, Equilibrium Isotherm, Experiments, Functional Group, Group, Hardness, Heavy Metal, Heavy Metal Ions, Hydrogen, Hydrogen Peroxide, Infrared, Infrared Spectroscopy, Interaction, Ions, Isotherm, Kinetics, Lagergren, Langmuir, Langmuir Model, Low Temperature, Mar, Metal, Metal Ion, Metal Ions, Metals, Model, Modified, Multicomponent System, Objective, pH, Potential, Pseudo First Order, Pseudo-First-Order, Pseudo-First-Order Equation, Recovery, Regeneration, Removal, Rights, Selectivity, SEM, Small, Solution, Solutions, Sorption, Sorption Capacity, Sources, Species, Spectroscopy, Structure, Surface, Suspension, Temperature, Time, Treatment, Uptake, Uptake Capacity, Wastewater, Wastewaters, Water, Work, Zn²⁺

? Saltalı, K., Sarı, A. and Aydın, M. (2007), Removal of ammonium ion from aqueous solution by natural Turkish (Yıldızeli) zeolite for environmental quality. Journal of Hazardous Materials, 141 (1), 258-263.

Full Text: 2007\J Haz Mat141, 258.pdf

Abstract: The purposes of this study were to investigate the removal efficiency of ammonium (NH₄⁺) ion from aqueous solution using the natural Turkish (Yıldızeli) zeolite and to characterize equilibrium isotherms. Experiments were carried out using batch method as a function of the solution pH, shaking time, dosage of adsorbent, and temperature. All these factors affected NH₄⁺ ion removal from aqueous solution. Equilibrium modelling data were fitted to linear Langmuir and Freundlich models. Dubinin–Redushckevich (D–R) isotherm was applied to describe the nature of ion exchange of NH₄⁺ and found that it occurred physically. Thermodynamics parameters such as change in free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) were also calculated. These parameters confirmed that ion exchange of NH₄⁺ by the zeolite was feasible, spontaneous and exothermic in nature. Based on the results, it can be concluded that the natural Turkish (Yıldızeli) zeolite is suitable for the removal of NH₄⁺ ions in wastewater treatments and agricultural purposes to in terms of sustainability of environmental quality.

Keywords: Adsorbent, Adsorption, Agricultural, Ammonium, Ammonium Removal, Bentonite, Clinoptilolite Zeolite, Copper, Dosage, Efficiency, Energy, Entropy, Environmental, Environmental Quality, Equilibrium, Freundlich, Ion, Ion Exchange, Isotherm, Isotherm, Isotherms, Langmuir, Metal-Ions, Modelling, Models, Natural, Natural Zeolite, Ni(II), Parameters, pH, Quality, Removal, Removal Efficiency, Sandy Soil, Solution pH, Sorption, Sustainability, Temperature, Thermodynamic Parameter, Tree Fern, Wastewater, Zeolite

? Liu, S.X., Chen, X., Chen, X.Y., Liu, Z.F. and Wang, H.L. (2007), Activated carbon with excellent chromium(VI) adsorption performance prepared by acid-base surface modification. Journal of Hazardous Materials, 141 (1), 315-319.

Full Text: 2007\J Haz Mat141, 315.pdf

Abstract: In the present work, activated carbon (AC) with excellent Cr(VI) adsorption performance especially at low concentrations was prepared by an acid-base surface modification method. Raw activated carbon (AC(0)) was first oxidized in boiling HNO₃ (AC(1)), then treated with a mixture of NaOH and NaCl (AC(2)). Batch equilibrium and continuous column adsorption were conducted to evaluate the adsorption performance. Boehm fitration, elemental analysis, and N₂/77 K adsorption isotherm methods were used to characterize the surface properties and pore structure of modified ACs. The results revealed that the modified AC exhibited excellent Cr(VI) adsorption performance in terms of adsorption capacity and adsorption rate: AC(2) > AC(1) > AC(0). Modification caused S-BET to decrease and the total number of surface oxygen acidic groups to increase. HNO₃ oxidization produced positive acid groups, and subsequently NaOH treatment replaced H⁺ of surface acid groups by Na+, and the acidity of AC decreased. The main cause of higher Cr(VI) adsorption capacity and rate for AC(2) was the presence of more oxygen surface acidic groups and suitable surface acidity. HNO₃-NaOH modification shows potential for the preparation of high quality AC for the effective removal of low concentrations of Cr(VI). (c) 2006 Elsevier B.V. All rights reserved.

Keywords: Acid, Acidity, Activated Carbon, Adsorption, Adsorption Capacity, Adsorption Isotherm, Adsorption Rate, Analysis, Aqueous-Solution, Base, Capacity, Carbon, Chemistry, Concentrations, Cr(VI), Elemental Analysis, Equilibrium, Groups, Hexavalent Chromium, HNO₃, Isotherm, Methods, Mixture, Modification, Modified, Oxygen, Performance, Properties, Quality, Removal, Structure, Surface, Surface Modification, Surface Properties, Treatment

? Oliveira, L.C.A., Gonçalves, M., Oliveira, D.Q.L., Guerreiro, M.C., Guilherme, L.R.G. and Dallago, R.M. (2007), Solid waste from leather industry as adsorbent of organic dyes in aqueous-medium. Journal of Hazardous Materials, 141 (1), 344-347.

Full Text: 2007\J Haz Mat141, 344.pdf

Abstract: The industrial tanning of leather usually produces considerable amounts of chromium-containing solid waste and liquid effluents and raises many concerns on its environmental effect as well as on escalating landfill costs. Actually, these shortcomings are becoming increasingly a limiting factor to this industrial activity that claims for alternative methods of residue disposals. In this work, it is proposed a novel alternative destination of the solid waste, based on the removal of organic contaminants from the out coming aqueous-residue. The adsorption isotherm pattern for the wet blue leather from the Aurea tanning industry in Erechim-RS (Brazil) showed that these materials present high activity on adsorbing the reactive red textile dye as well as other compounds. The adsorbent materials were characterized by lR spectroscopy and SEM and tested for the dye adsorption (reactive textile and methylene blue dyes). The concentrations of dyes were measured by UV-vis spectrophotometry and the chromium extraction from leather waste was realized by basic hydrolysis and determined by atomic absorption. As a low cost abundant adsorbent material with high adsorption ability on removing dye methylene blue (80 mg g^-1) and textile dye reactive red (163 mg g^-1), the leather waste is revealed to be a interesting alternative relatively to more costly adsorbent materials. (c) 2006 Elsevier B.V. All rights reserved.

Keywords: Absorption, Activity, Adsorbent, Adsorption, Adsorption Isotherm, Adsorption Process, Alternative Methods, Brazil, Chromium, Chromium, Collagen, Concentrations, Contaminants, Contaminated Effluents, Cost, Costs, Dye, Dye Adsorption, Dyes, Effluents, Environmental, Extraction, Hydrolysis, Industrial, Isotherm, Landfill, Leather Waste, Limiting Factor, Materials, Methods, Methylene Blue, Organic, Organic Contaminants, Removal, Residue, SEM, Solid Waste, Spectrophotometry, Spectroscopy, Textile Dye, Waste, Water

? Venkata Mohan, S., Ramanaiah, S.V., Rajkumar, B. and Sarma, P.N. (2007), Removal of fluoride from aqueous phase by biosorption onto algal biosorbent (Spirogyra Sp –I02): Sorption mechanism elucidation. Journal of Hazardous Materials, 141 (3), 465-474.

Full Text: 2007\J Haz Mat141, 465.pdf

Abstract: This communication presents results pertaining to the adsorptive studies carried out on fluoride removal onto algal biosorbent (Spirogyra IO2). Batch sorption studies were performed and the results revealed that biosorbent demonstrated ability to adsorb the fluoride. Influence of varying the conditions for removal of fluoride, such as the fluoride concentration, the pH of aqueous solution, the dosage of adsorbent, the temperature on removal of fluoride, and the adsorption-desorption studies were investigated. Sorption interaction of fluoride on to algal species obeyed the pseudo first order rate equation. Experimental data showed good fit with the Langmuir’s adsorption isotherm model. Fluoride sorption was found to be dependent on the aqueous phase pH and the uptake was observed to be greater at lower pH. Maximum fluoride sorption was observed at operating 300C operating temperature. Adsorption-desorption of fluoride into inorganic solutions and distilled water was observed and this indicated the combined effect of ion exchange and physical sorption phenomena. Significant changes in the FT-IR spectra was observed after fluoride sorption which is indicative of the participation of surface function groups associated with hydrogen atoms in the carboxylic groups in sorption interaction. From X- ray photoelectron spectroscopy (XPS) analysis a marginal increase in the area for the binding energy peak at 287.4 eV was observed which could be due to the formation of -C- F- bonds. Thermogravimetric (TGA) analysis of the fluoride loaded sorbent showed that the biosorbent underwent three steps decomposition process when heated from 25C to 100C. The maximum weight loss was observed to be between 200-400C and 700-800C.

Keywords: Biosorption, Algae, Spirogyra, Biosorbent, Kinetics, Adsorption-Desorption, Isotherms, SEM, FT – IR, XPS and TGA

? Ji, Z.Y., Yuan, J.S. and Li, X.G. (2007), Removal of ammonium from wastewater using calcium form clinoptilolite. Journal of Hazardous Materials, 141 (3), 483-488.

Full Text: 2007\J Haz Mat141, 483.pdf

Abstract:The paper concerns the removal of ammonium ions from aqueous solution using a modified clinoptilolite- Ca²⁺-formed clinoptilolite (CaY) prepared from natural clinoptilolite. The batch study results show that the pH has an effect on ammonium adsorption capacity as it can influence both the character of the exchanging ions and the clinoptilolite itself; the CaY has a high selectivity to NH₄⁺ and the exchange decreases with increasing temperature; ammonium ion uptake onto CaY was suitably described by the Langmuir model. The column results indicated that the effluent of simulated wastewater treated with CaY could meet the integrated wastewater discharge standard of China, and CaY can be circulated through regenerating by Ca(OH)₂.

Keywords:Ammonium Removal, Clinoptilolite, Wastewater, Thermodynamics

? Chen, C.C., Lu, C.S., Chung, Y.C. and Jan, J.L. (2007), UV light induced photodegradation of malachite green on TiO₂ nanoparticles. Journal of Hazardous Materials, 141 (3), 520-528.

Full Text: 2007\J Haz Mat141, 520.pdf

Abstract: The photodegradation of malachite green (MG), a cationic triphenylmethane dye, is examined both under different pH values and amounts of TiO₂. After 15 W UV-365 nm irradiation for 4 h, ca. 99.9% of MG was degraded with addition of 0.5 g L^-1 TiO₂ to solutions containing 50 mg g^-1 of the MG dye. The HPLC-PDA-ESI-MS technique was used to obtain a better understanding on the mechanistic details of this TiO₂-assisted photodegradation of the MG dye with UV irradiation. Five intermediates of the process were separated, identified, and characterized for the first time. The results indicated that the N-de-methylation degradation of MG dye took place in a stepwise manner to yield mono-, di-, tri-, and tetra-N-de-methylated MG species generated during the processes. Under acidic conditions, the results indicated that the photodegradation mechanism is favorable to cleavage of the whole conjugated chromophore structure of the MG dye. Under basic conditions, the results showed that the photodegradation mechanism is favorable to a formation of a series of N-de-methylated intermediates of the MG dye.

Keywords: Cleavage, Degradation, Dye, First, Induced, Irradiation, Malachite Green, Mechanism, Mg, N-De-Methylation, Nanoparticles, pH, Photodegradation, Solutions, Species, Structure, TiO₂, TiO₂ Nanoparticles, Triphenylmethane, Triphenylmethane Dye, Understanding, UV, UV Light

? Dinçer, A.R., Güneş, Y. and Karakaya, N. (2007), Coal-based bottom ash (CBBA) waste material as adsorbent for removal of textile dyestuffs from aqueous solution. Journal of Hazardous Materials, 141 (3), 529-535.

Full Text: 2007\J Haz Mat141, 529.pdf

Abstract: A locally available CBBA waste material was used as adsorbent for removal of reactive dyes from synthetic textile wastewater. This study presents the results of our investigation on color removal from synthetic wastewater containing Vertigo Blue 49 (CI Blue 49) and Orange DNA13 (CI Orange 13) by adsorption onto CBBA waste material. The effectiveness of CBBA waste material in adsorbing reactive dyes from aqueous solutions was studied as a function of contact time, initial dye concentration and pH by batch experiments. Leachability of waste material was also evaluated using standard leaching test with deionized water (DIN38414-S4). pH 7 was more favorable for color removal from both Vertigo Blue 49 (CI Blue 49) and Orange DNA (CI Orange 13). Dyestuff adsorption capacities of CBBA for Vertigo Blue 49 and Orange DNA13 were 13.51 and 4.54 mg dye/g adsorbent, respectively. The adsorption isotherms for the CBBA can be better described by the Freundlich isotherm. The results showed that the dyestuff uptake process for both dyes followed the second-order kinetics. The bottom ash used in this study is not classified as ecotoxic/hazardous material according to the French proposal for a criterion and evaluation methods of waste ecotoxicity (CEMWE) and the German regulation on Hazardous Waste Classification (HWC).

Keywords: Acid Dyes, Activated Carbon, Adsorbent, Adsorption, Adsorption Isotherms, Aqueous Solution, Ash, Batch Experiments, Bottom Ash, Color Removal, Column Operations, Concentration, Dna, Dye, Dyes, Dyestuff, Ecotoxicity, Effectiveness, Equilibrium Uptake, Evaluation, Fly-Ash, Freundlich, Freundlich Isotherm, Function, Investigation, Isotherm, Isotherms, Kinetics, Leaching, Malachite Green, Methods, Methylene-Blue, p, Process, Reactive Dye, Reactive Dyes, Regulation, Removal, Rhodamine-B, Second-Order Kinetics, Sorption Dynamics, Standard, Test, Textile, Uptake, Waste, Wastewater, Wastewater Treatment, Water

? Akhtar, M., Hasany, S.M., Bhanger, M.I. and Iqbal, S. (2007), Sorption potential of Moringa oleifera pods for the removal of organic pollutants from aqueous solutions. Journal of Hazardous Materials, 141 (3), 546-556.

Full Text: 2007\J Haz Mat141, 546.pdf

Abstract: Moringa oleifera pods Lamarck (Drumstick or Horseradish) is a multipurpose medium or small size tree from sub-Himalayan regions of north-west India and indigenous to many parts of Asia, Africa, South America and in the Pacific Caribbean Islands. Its pods (MOP) have been employed as an inexpensive and effective sorbent for the removal of organics i.e. benzene, toluene, ethylbenzene and cumene (BTEC) from aqueous solutions using HPLC method. Effect of different parameters i.e. sorbent dose (0.05-0.8g), agitation time (5-120 min), pH (1-10), temperature (283-308 K) and concentration of sorbate (1.3 to 13×10^-3), (1.1 to 11×10^-3), (0.9 to 9×10^-3), (0.8 to 8×10^-3) mol dm^-3, on the sorption potential of MOP for BTEC have been investigated. The pore area and average pore diameter of the MOP by BET method using nitrogen as a standard are calculated to be 28.06±0.8 m²g^-1 and 86.2±1.3 nm respectively. Freundlich, Langumir and Dubinin-Radushkevich (D-R) sorption isotherms were employed to evaluate the sorption capacity of MOP. Sorption capacities of BTEC onto MOP have been found to be (46±10, 84±9, 101±4, 106±32) mmol g^-1 by Freundlich, (8±0.1, 9±0.1, 10±0.3, 9±0.1) m mol g^-1 by Langumir and (15±1, 21±1, 23±2, 22±3) m mol g-1 by D-R isotherms respectively, from BTEC solutions at 303 K. While the mean energy of sorption process (9.6±0.3, 9.2±0.2, 9.3±0.3, 9.5±0.4) kJ mol-1 for BTEC is calculated by D–R isotherm only. Rate constant of BTEC onto MOP (0.033±0.003, 0.030±0.002, 0.029±0.002, 0.027±0.002) min^-1 at solution concentration of 1.3×10^-3, 1.1×10^-3, 0.9×10^-3 and 0.8×10^-3 mol dm^-3 and at 303 K have been calculated by employing Lagergren equation. Thermodynamic parameters ∆H (-8±0.4, -10±0.6, -11±0.7, -11±0.7) kJ mol^-1, ∆S (-22±2, -26±2, -27±2, -29±3) J mol^-1K^-1 and∆G303K (-0.9±0.2, -1.9±0.2, -2.3±0.1 and -2.6±0.2) kJ mol^-1 were also estimated for BTEC respectively at temperatures (283–308 K). The negative values of ∆H, ∆S and ∆G suggest exothermic, stable (with no structural changes at solid-liquid interface) and spontaneous nature of sorption process under optimized conditions. MOP has been used extensively to accrue and then to preconcentrate benzene, toluene and ethylbenzene in wastewater sample.

Keywords: Moringa Oleifera (Drumstick) PODS, Sorption, Benzene, Toluene, Ethylbenzene, Cumene

? Giménez, J., Martínez, M., de Pablo, J., Rovira, M. and Duro, L. (2007), Arsenic sorption onto natural hematite, magnetite, and goethite. Journal of Hazardous Materials, 141 (3), 575-580.

Full Text: 2007\J Haz Mat141, 575.pdf

Abstract: In this work the sorption of As(III) and As(V) on different natural iron oxides (hematite, magnetite, and goethite) has been studied as a function of different parameters. The sorption kinetics for the three iron oxides shows that equilibrium is reached in less than two days and the kinetics of sorption seems to be faster for goethite and magnetite than for hematite. The variation of the arsenic sorbed on the three different sorbents as a function of the equilibrium arsenic concentration in solution has been fitted with a non-competitive Langmuir isotherm. The main trend observed in the variation of the arsenic sorbed with pH is the decrease of the sorption on the three sorbents at alkaline pH values, which agrees with results found in the literature. Highest As(III) sorption was observed on hematite surface in all the pH range compared to goethite and magnetite. Natural minerals studied in this work had similar sorption capacities for arsenic than synthetic sorbents.

Keywords: Iron Oxides, Langmuir Isotherm, Metal Sorption, Sorption Kinetics

? Suksabye, P., Thiravetyan, P., Nakbanpote, W. and Chayabutra, S. (2007), Chromium removal from electroplating wastewater by coir pith. Journal of Hazardous Materials,